dcb: Add missing error check in dcb_ieee_set()

Missing error checking before nla_parse_nested().

Reported-by: Mark Rustad <mark.d.rustad@intel.com>
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c
index f54c784..e954d4c 100644
--- a/net/dcb/dcbnl.c
+++ b/net/dcb/dcbnl.c
@@ -1368,6 +1368,9 @@
 	if (!ops)
 		return err;
 
+	if (!tb[DCB_ATTR_IEEE])
+		return -EINVAL;
+
 	err = nla_parse_nested(ieee, DCB_ATTR_IEEE_MAX,
 			       tb[DCB_ATTR_IEEE], dcbnl_ieee_policy);
 	if (err)